Hot-air furnace



IA. PA'HVIAINEN. HOT AIR FURNACE.

APPLlcAloN man MAY 22, 1922.

Patented Nov. 28, 1922-..

2 SHEETS-SHEET l.

A. PARVIAINTEN HOT AIB FURNACE.

APPLICATION FILED MAYZZ, 1922.

mamon,

. MMA/mmf Patented Nov.. 28, 1922..

litiiittvtlhl STA rate raar 'i HOT-AIR FURNACE.

Application filed May 22,

To @ZZ ze/wm t may concern Be it known that I, ANDREW PAnvIAINnN, a citizen of the United States, residing at Cromwell, in the county of Carlton and State of Minnesota, have invented certain new and useful Improvements in a Hot-Air Furnace; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

rlhis invention relates to an improved hot air furnace, and it has for its principal object to generally improve upon heating devices of this class by providing one'of comparative simplicity and durability which is practical and embodies novel means for securing a uniform distribution of the heated air within the outer casing, this means being a chamber in which heat absorbing elements are positioned for retaining and effectively radiating' the heat against the wall of the chamber with which the air contacts to become heated.

@ther objects and advantages of the invention will be apparent during the course of the following description.

ln the accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same:

vFigure l is a front elevation of a furnace constructed in accordance with thisginvene tion. i i

Figure 2 is a central vertical section thereof.

liigure 3 is a section taken at right angles te lfigure 2 on the line 3 8 of Figure 2.

vFigure 4t is a horizontal section taken on the lines 4l-/t respectively of Figures 2 und 3.

in the drawings, the numeral 'l represents a metal casing having cold air intake open ings 2 at its bottom and hot air outlet openings 3 at :its top. t may be mentioned here that this furnace is of the portable type and is designed especially for burning wood. However, it is adaptable for use for coal burning too and may be installed in the cellar, and when so installed, the usual hot air conveying' pipes will be connected to the discharge openings 3. rlhe casing is equipped on its rear side with a vertical smoke pipe l having a suitable damper or valve arranged therein. The casing is further equipped with a plurality oi" doors at its 1922. Serial No. 562,932.

front or permit access to be had to the interior of the casing for inserting fuel, removing ashes or for other purposes which will be made apparent as the description goes on. lt may be conveniently stated here that a passage 6 for the smoke and heated particles carried therewith is arranged at the center of the/bottom of the casing and this passage connects at its rear end with the aforesaid smoke pipe and terminates short of 7 0 i lt may also be conveniently et being such that it insures `eik-active heating of the air even when the tire becomes low. rihe means .in its preferred form comprises a compartment 8 the wall 9 of which is cor- `rugated and is 4spaced from the walls of the aforesaid casing to provide anair circulating space l0. Arranged within this compartment 8 is a re boX `l1 which is supported in spaced relation from the bottom of the, casing on the aforesaid passage 6. This iire box is open at its top and a plurality of .bars l2 extend transversely across this end and rest on the side walls to provide a grate. fis shown, stones or the like v13 are adapted to be packed in the compartment 8 and these stones are to be such y and retain the heat, the same being heated `to a high degree by the smoke which is compelled to pass upwardly tlnfough the aforesaid grate and. between the packed stones.

as: tov` yeiiectively absorb 'ilo insure effective and uni forni distribution of the smoke within this compartment 8, li, employ` divergent baiiie plates i4, these being associated with the upper end of the fire box and having their upper edges terminating adjacent the wall of the compartment to provide a limited passage for the smoke between this wall and baffle. I am led to state here that these baiiies and aforesaid wall 9 are held together at the proper spaced relation by a plurality of stay bolts l5. AL though it is not essential, corrugated plates 16 are placed within the compartment and rest against the fire box with the baliies, these plates serving to act in conjunction with. the

" formed by the battles,

stones for absorbing and radiating heat against the wall of the compartment so that the air will be evenly distributed iny this compartment and will be caused to contact the entire surface of the compartment to insure a thorough heating of the air. l

n the operation it will be seen that the flames from the fire box 11 will impingel upon the stones 13 resting on the grate bars l2 and will in conjunction with the escaping smoke, thoroughly heat these stones. Since they are of a quality to absorb the heat, it will be seen that the heat will be gradually adiated from them to heat the wall of the compartment S to a high degree. Hence, 'he air which enters the aforesaid casing 1 through the openings 2 will contact the sur face of this compartment and will become highly heated before it escapes through the discharge openings 3. Hence, a highly desirable and practical portable `furnace is thus provided. It is to be emphasized that ywith the particular construction of furnace described, a considerable amount of fuel will be saved. and practical experiencer with a furnace constructed in accordance with this invention has disclosed the fact that even after the fire has been completely extinguished, the heat retaining elements will serve to keep the wall of the compartment heated for quite some period of time. Thus, even when the fire is out the furnace will function. to heat the air whichv circulates through it. It is evident that a furnacepof this type will be highly desirable in that it will not require keeping of the fire over night, yet it will automatically function to keep the house comfortable. Attention is also directed to the fact that with the parv ticular arrangement shown, the escaping particles of combustion and smoke are compelled to pass upwardly through the heat absorbing elements over the grate, downwardly through the restricted passages and around the lirebor vin order to enter the discharge conduit. Consequently, intense heating ofthe inner casing or compartment is assured,

By carefully considering the description in connections/ith the drawings, persons familiar with devices of this class will doubtless be able to obtain a clear understanding of the invention. Therefore, a more lengthy and detailed description is deemed unnecessary.

Since probably the best results may be obtained with the construction and arrangement herein shown and described, this is taken as the preferred embodiment of the invention. However, l wish it to be understood that minor changes coming within the scope of the invention as claimed may be resorted to if desired.

l claim:

l. A hot air furnace comprising inner and outer 'spaced casings between which cool air is adapted to pass to be heated, a smoke discharge conduit extending through said inner casing, a lire box arranged in said last named casing, being supported on the conduit, a grate supported on the upper open side of said box, and heat absorbing and radiating elements arranged in said inner casing and partially surrounding the ire ybox conduit, whereby to compel the smoke and products of combustion to follow a tortuous passage around-"the fire boX before entering the discharge conduit.

2. A hot air furnace comprising a casing, a smoke pipe, a passage for the smoke communicating with said pipe and extend* ing across the bottom of said casing and terminating in spaced relation from one `of the walls thereof, a (.'fompartnient arranged in said casing and having its wall spaced from the walls of said casing to provide a space for the circulation of air, a plurality of heat absorbing and radiating elements positioned in said compartment, the `latter communi eating with said smoke passage, and a firebox resting on said passage and having an upper open end with a grate positioned thereon to permit passage of the smoke between said heat absorbing elements.

3. Ahot air furnace comprising a casing having a smoke pipe and a passage connectedto said smoke pipe and extending across the inner face of the bottom of said casing and terminating in spaced relationr from one of the Walls thereof, a compartment arranged inside of said casing and covering' said smoke passage, the wall of said conipartment being spaced from the walls of said casing to provide a space for circulation of heated air, heat absorbing elements in the compartaient, a lirefliiox supported on said passage and having` its upper open end covered by a grate throughuthe bars of which the smoke is adapted to pass for heating said elements, and baffle plates associated with said iireboX and arranged in Vsaid compartment for creating a uniform distribution of the smoke through said eley ments.

ln testimony whereof l have hereunto set "my hand.

ANDREW rAnviaiNnN. 

